Process of making binderless briquettes



May 17, 1960 G. KOMAREK ET AL 2,937,030

PROCESS OF MAKING BINDERLESS BRIQUETTES Filed Feb." 14, 1957 2Sheets-Sheet 1 FIG. I.

J RAW GOAL FEED l T 2 L FURNACE x .q 20 i 3 WH- I ,8 I INVENTORS I I561/5 TAV mums/r KARL R. mun/m l6 l7 ATTORNEYS May 17, 1960 G. KOMARE'KETAL PROCESS OF MAKING BINDERLESS BRIQUETT'ES 2 Sheets-Sheet 2 FiledFeb. 14,1957

INVENTORS GUSTAV KOMAREK mm. m KOMAHEK ATT( )RNEYS NYQQ Qwk MI I Mk195506 2,937,080 PROCESS on Mame BINDERLESS BRIQUETTES Gustav Kornarekand Karl R. Komarek, Chicago, Ill., assignors to Komarek-Greaves andCompany, Chicago, 111., a corporation of Illinois Application February14, 1957, Serial No. 640,238

10 Claims. or. 44-10 The present invention is concerned with a processfor the production of binderless briquettes from coal.

It is an object of the present invention toprovide a more desirable wayof feeding coal to the briquetting machine.

It is a further object of this'invention to control the temperature ofthe coal.

It is still another object of this invention to control the velocity ofthe coal.

It is another object of this invention to control the amount ofoxidation of the coal.

It is still another object of this invention to provide a method ofsimultaneously cooling the finishedbriquettes and preheating theunprocessed coal.

The accomplishment of these and other objects of the invention willbecome apparent from a reading of the following description and thefigures of the drawing.

The novel process involves feeding coal particles of fineness from 20mesh or coarser up to 300 mesh or finer by means of a hot gas streaminto a cyclone separator from which the coal particles are separatedfrom the gas and fed into a conventional briquetting machine. A portionof the gas is vented off to the atmosphere,

, while the remainder. of the gas is recycled and fed by means of ablower into the gas stream at a point between the gas coming from afurnace (the main source of gas) and the point of injection of the coalparticles into the gas stream, or as shown in the drawings, which willbe referred to with particularity hereinafter, the recycled gas may befed into the gas stream at a point before that at which the gas from thefurnace enters the stream. The amount of gas vented to the atmosphere isalways equal to the amount of gas introduced at the burner plus anywater vapor evaporated from the coal. The recycling of the hot gases hasseveral advantages over the prior art methods of feeding the coal to thebriquetting machine. The first advantage is heat economy. The recycledgas will assist in heating the coal and, hence, a lesser amount of fuelwill be requiredto introduce heated gas into the system. The coal can beconveyed at the most suitable velocity throughv the system withoutregard to the amount of heat or gases being supplied by the furnace.Since the velocity of the gases in the system is independent ofthe'furnace, but controlled only by the speed of the blower, thecharacter of the gases may be made either oxidizing or reducing, asrequired, for most eflicient processing of the coal. More or less heatmay be furnished from the furnace in order to heat the coal to the mostdesirable processing temperature Without regard to the initialtemperature of the coal and without effecting the'velocity of the coalor gases through the system. This provides the necessary flexibility toprocess coals of diverse chemical composition and of widely divergentinitial temperature conditions under conditions most favorable forv eachcoal. It has long been recognized, for example, that satisfactorybriquettes for most purposes are-not pro- States Patent bustion.

2,937,080 Patented May 17, 1960 duced from coals with a high swellingindex,,eig.,, a swelling numberabove7 British standard swelling test. Ona test with .coal (New River coal) of highv swelling number, e.g., over9+, the briquetted coalof the briquettesshowed' a satisfactory swelling,number, namely, of 7 It has been established that, with the equipmentherein described, satisfactory briquettes can be made from such coalswith greatly, reduced swelling properties-by controlling the amount-offree air contained within the system, e.g.,.by using 10% to 50%,preferably. 25%,, air and the balance of the gas beingthe products.of.com.- Coals of low swelling.index,,e'.g., a swelling index of lessthan 5, require no free air in the system. in order to formbriquetteswith satisfactory. properties.- The process and equipment hereindescribed, therefore,v serve a dual purpose, not only to producebriquettes with satisfactory physical strength, but also with.satisfactory burning properties. as well..

In a preferred form of operating the present invention, the briquettesare discharged from the briquette press by means of a. chute or othersuitable conveyor into a bin or hopper and admixed with the unprocessedcoal which is fed into the'bin in suitable. quantity froman independentconveyor. The bin is so sizedthat a suitable contact time, e.g., about10 to 20 minutes,.be-- tween the unprocessed coal and thefinishedbriquettes Will'bring the briquettes'and unprocessedcoal intosubstantialthermal equilibrium. The cooled briquettes and preheated coal aredischarged-continuously from-the bottom of the bin'by any suitableconveyor and screened;

'the'finished briquettes being now ready for storage or sults in evengreater heat economy than the method wherein the briquettes are not usedto preheat the incoming coal. Briquettes have a tendency to ignite spon'taneously if not cooled before stockpiling. When operating according tothe preferred form of the inven tion, this problem is overcome as thebriquettes are adequately cooled by the incoming coal.

The temperature'of the gases within the system, after admixture with thegases: from the furnace, should be from 500 F. to 1.000 F. After'thepreheatedcoalis introduced into the gas stream, the temperature of thesegases drops rapidly to' 300 F. to 700 F. The temperatureof' these gasesat the cyclone is about 5 F. hotter than the temperature of the coal.The temperature of the coal shouldbe maintained between about 300 F. to"700 F. when it reaches'the briquetting machine rolls. After admixture ofthe briquettes with the un treated coal, the temperatureof thebriquettes drops toabout 200 F.-to 300 F., e.g., 250"F.

The percentage of recycled gas to total gas is'us u'ally between about40-%-and and preferably about 60% The temperature of the coal justbeforeitreaches-the" briquetting machine should be just below thesoftening .point, e.g., point of nascent plasticity,- ofthe coalfor"maximum efficiency in operation; Many coals can be compressed intosuitable agglomerates within the temperature range of'ab'oiit 300 F:to700" F.

Referring to the drawing:

Figure 1 is'a. schematic drawin g of a suitable 1 through pipe 2 toconduit 3. The burner in the furnace is under pressure from a fan (notshown) to blow the gas upwardly. Raw coal is introduced through hopper 5into conduit 3, thence through connection 6 into cyclone separator 7. Apart of the gas is removed through vent 8 while the remaining gas passesthrough connection 9 into conduit 10 from whence it is recycled and fedby means of a blower 21 into conduit 3. The recycled gas may enter thegas stream at a point along conduit 3 intermediate the gas coming fromthe furnace (the main source of gas) and the point of injection of thecoal particles into the gas stream, but as shown in Figure 1, preferablythe recycled gas is introduced into conduit 3 in advance of the gas fromthe furnace 1 which enters conduit 3 through pipe 2.

The coal is separated from the gas particles in the cyclone separatorand passes through airlock 11 into chute 12 from whence it falls betweenbriquetting rolls 13 in briquetting machine 14. The briquetted coal isremoved onto a chute 22 (Figure 2). The briquetting machine is supportedby stands 15 and 16. Motor 17 is also mounted on stand 16. Shaft 18 runsfrom motor 17 and carries a'pulley (not shown) upon which is mounted aseries of belts which are also entrained over pulley 19 to which isconnected shaft 20 which is attached through appropriate means to thebriquetting rolls.

Referring to Figure 2, the hot briquettes emerge from the briquettingmachine on chute 22 and fall into mixing bin 23. Ground raw coal feed isintroduced into mixing bin 23 through conduit 24. Bin 23 is so sizedthat there is an'average contact time between the raw coal feed and thehot finished briquettes of about 10 to 20 minutes, at the end of whichtime the raw coal and briquettes will be in substantial heatequilibrium. The mixture of raw coal feed and briquettes fall ontoendless conveyor 25 which is entrained over pulleys 26 and 27 which areconnected to a source of power (not shown) so as to advance the conveyorcontinuously carrying along with it the mixture of heated raw coal andcooled finished briquettes. As the conveyor passes over pulley 27, theraw coal and finished briquettes fall off onto screen 28. The screen isselected so as to have openings large enough to permit the passage ofthe heated raw coal therethrough, but small enough to prevent thepassage of the cooled briquettes therethrough. The cooled briquettesemerge from the lower end of the screen 28 ready for use. The heated rawcoal passes through screen 28 into preheated coal chute 29 and thence,by conveyor means 30, to hopper 5. From hopper 5 the preheated coalpasses by way of coal feeder 31 to conduit 3.

Example 1 In a typical example, embodying the features of our inventionand using the preferred form of the apparatus, the following conditionswere employed. The gas from the furnace on analysis showed carbondioxide, nitrogen, oxygen, and standard products of combustion,depending on the fuel used. The blower was operated to give a velocityof gas of about 3000 to 6000 feet per minute. Approximately 60% of thegas was recycled. Raw coal of 9+ swelling number and mesh size betweenabout 20 and 100 was fed into mixing bin 23 while, simultaneously, hotbriquettes also were fed into the mixing bin at a rate equivalent to theraw coal.-

Example 2 the coal at the time it reached the briquetting machine was295 F.

Example 3 Example 2 was repeated utilizing a high swelling coal having asoftening point of about 505 F. and a mesh size of about 20 to 100.About 40% of the gas was recycled. Furnace gases were employed having aninitial. temperature of 750 F. This temperature dropped to 500 F. afteradmixture with the coal, and the temperature of the coal at the time itreached the briquetting machine was 495 F.

Example 4 Example 2 was repeated utilizing a high swelling coal having asoftening point of about 705 F. and a mesh size of about 20 to 300.About of the gas was recycled. Furnace gases were employed having aninitial temperature of 1000" F. This temperature dropped to 700 F. afteradmixture with the coal, and the temperature of the coal at the time itreached the briquetting machine was 695 F.

While the invention has been described in accordance with the preferredembodiments, it is apparent that many variations and modification may beresorted to without departing from the scope of equivalents within thepurview and spirit of this invention, as defined in the appended claims.

This application is a continuation-in-part of our application Serial No.413,929, filed March 3, 1954, and now abandoned.

We claim:

1. The process of handling raw coal being fed to a briquetting machinecomprising feeding coal into a stream of hot gas, moving the coaldirectly with the aid of said gas to the briquetting machine whilesimultaneously venting off part of the gasand recycling the remainder ofthe gas to the stream of gas used to transport the coal, the temperatureof the gas being between about 300 F. and 700 F. after admixture withthe coal and the temperature of the coal being between about 300 F. and700 F. when it reaches the briquetting machine rolls, said tempcratureof the coal being sufiiciently high to completely prepare the coal forbriquetting.

2. A process as in claim 1 in which the amount of recycled gas to totalgas is between about 40% and 80%.

3. The process of claim 1 wherein the gas from the extraneous source isintroduced into the main gas stream at a point intermediate theintroduction of the recycled gas thereof and the point where the coal isintroduced into the gas stream.

4. A process according to claim 1 including the additiOnal steps ofmixing the hot briquettes formed with the raw coal, whereby the raw coalis preheated and the briquettes are cooled, separating the briquettesfrom the preheated raw coal and then feeding the preheated raw coal intothe hot gas stream.

5. The process of claim 4 wherein the preheated coal is passed to acyclone separator with the aid of said gas, separating the coal from thegas in said separator, venting a part of the gas directly from theseparator to the atmosphere, recycling the rest of the gas, and allowingthe coal to fall from said cyclone separator to said briquetting rolls.

6. The process of claim 4 wherein the recycled gas is introduced intothe main gas stream at a point intermediate the introduction of gas froman extraneous source thereof and the point Where the coal is introducedinto the gas stream.

7. The process of claim 1 in which the coal passes directly from saidcyclone separator through an airlock and thence to the briquettingmachine.

8. The process of claim 1 in which the temperature of the gas afteradmixture with the coal is 300 F. 5

9. The process of claim 1 in which the temperature of the gas afteradmixture with the coal is 700 F.

10. The process of claim 1 wherein the coal and gas mixture is under theinfluence of the atmosphere from their point of intermingling to theirpoint of separation. 10

6 References Cited in the file of this patent UNITED STATES PATENTS

1. THE PROCESS OF HANDLING RAW COAL BEING FED TO A BRIQUETTING MACHINECOMPRISING FEEDING COAL INTO A STREAM OF HOT GAS, MOVING THE COALDIRECTLY WITH THE AID OF SAID GAS TO THE BRIQUETTING MACHINE WHILESIMULTANEOUSLY VENTING OFF PART OF THE GAS AND RECYCLING THE REMAINDEROF THE GAS TO THE STREAM OF GAS USED TO TRANSPORT THE COAL, THETEMPERATURE OF THE GAS BEING BETWEEN ABOUT 300*F. AND 700*F. AFTERADMIXTURE WITH THE COAL AND THE TEMPERATURE OF THE COAL BEING BETWEENABOUT 300*F. AND 700*F. WHEN IT REACHES THE BRIQUETTING MACHINE ROOLS,SAID TEMPPERATURE OF THE COAL BEING SUFFICIENTLY HIGH TO COMPLETELYPREPARE THE COAL FOR BRIQUETTING.